1. Field of the Invention
The present invention relates to a noise damper disposed in a tire cavity formed by a pneumatic tire and wheel rim.
2. Related Art
In recent years, as the mechanical noise from automobiles especially passenger cars is greatly reduced, pneumatic tires especially those for passenger cars are strongly required to reduce their noise. There are many factors, but a circumferential resonance of annular air in the tire cavity is one of major factors. Usually, a resonance peak occurs in a frequency range of from 50 to 400 Hz according to the tire size.
To reduce such a resonance noise, a noise damper made of a sponge-like material disposed in the tire cavity has been proposed in the U.S. Pat. Nos. 6,726,289 and 6,729,373.
When a strip of a sponge-like material is to be fixed to tire with adhesive, usually it is necessary to remove a mold release agent and buff the bonding face, otherwise a separation failure is caused at the ends of the strip. Thus, the working efficiency is not so good. If separated the strip is very liable to causes flutter during running, and the rotational balance of the tire is lost. The problems of flutter and rotational balance also arise in case of a damper loosely inserted around the wheel rim.